如何在 React.Js 中背景图像 css？

Question

This is my tree folder

├── public
│   ├── favicon.ico
│   ├── image.jpeg
│   ├── index.html
│   ├── logo192.png
│   ├── logo512.png
│   ├── manifest.json
│   └── robots.txt
├── README.md
└── src
    ├── App.css
    ├── App.js
    ├── App.test.js
    ├── index.css
    ├── index.js
    ├── logo.svg
    ├── reportWebVitals.js
    └── setupTests.js

This is my App.css

.App {
  text-align: center;
  background: url("/image.jpeg");
}

This is my App.js

import "./App.css";

function App() {
  return (
    <div className="App">
      <h1>asdasdasd</h1>
    </div>
  );
}

export default App;

I'm triying to add background-image to App.js but react throws this message

Failed to compile.

./src/App.css (./node_modules/css-loader/dist/cjs.js??ref--5-oneOf-4-1!./node_modules/postcss-loader/src??postcss!./src/App.css)
Error: Can't resolve '/image.jpeg' in '/home/ivan/Documents/code/REactJs/portafolio/src'

I'm dev on ubuntu 20, node version is v12.19.0

BTW I created this app yesterday and I dosen't work, but I have an old app I created a month ago and It works fine.

Answer 1

I don't think your App.css file can read images from your public folder, due to React's import restrictions from outside the src folder ( The create-react-app imports restriction outside of src directory ). Instead, add an inline style to App

import "./App.css";

function App() {
  return (
    <div className="App" style={{ backgroundImage: "url('/image.jpeg')" }}>
      <h1>asdasdasd</h1>
    </div>
  );
}

export default App;

Answer 2

You are looking for image.jpeg in the wrong directory. Your image.jpeg is found in /public, so try looking for it in background: url("../public/image.jpeg"); instead of background: url("/image.jpeg");

Answer 3

I have faced issues with background image urls.

On the internet, I found 2 answers:

1. If the images are kept in public directory, use absolute path.
2. If the images are kept in src directory, use relative path.

I have observed that these answers did not work if the css file or style is in one or more level deeper from the src directory.

├── public
│   ├── favicon.ico
│   ├── image.jpeg
│   ├── index.html
│   ├── logo192.png
│   ├── logo512.png
│   ├── manifest.json
│   └── robots.txt
├── README.md
└── src
    ├── App.css
    ├── App.js
    ├── a
    │   └── b
    │       ├── c.js
    │       └── c.css
    ├── App.test.js
    ├── index.css
    ├── index.js
    ├── images
    │   └── sample.png
    ├── logo.svg
    ├── reportWebVitals.js
    └── setupTests.js

The following would work, as .logo is kept in src/index.css :

.logo {
  background-image: url(images/sample.png)
}

But, the following will not, as the same is kept in a/b/c.css :

.logo {
  background-image: url(images/sample.png)
}

Finally, I learnt that, using absolute path works in all the scenarios. That is, the following works in all levels.

.logo {
  background-image: url(/images/sample.png)
}

The above also means that, using absolute path when the files are kept in public is not valid.

The whole thing is here .

Further reference:

1. https://stackoverflow.com/a/69615870/6999951
2. https://surajsharma.net/blog/background-image-in-react